My 2008 4/4 was bought with 7000 miles on the clock. It had had one king pin replaced already.
I chose to replace both with hard chromed king pins soon after acquisition and wrapped the pins / springs in Chamoise leather gaiters held in place by cable ties to keep the grit and road grime out. I grease at approximately 500 mile intervals myself and KNOW THE JOB IS DONE. I have done another 37,000 miles since that time without any further trouble from the king pins.
I had a local engineering shop do the reaming, but I may invest in a reamimg tool and do the job myself next time. I believe the fit within the bronze bushes should be an easy push fit rather than a tight interference fit. Too tight and the steering takes too many miles to free up.
